Andrew's git - gitweb.git/blob

   1/*
   2 * git gc builtin command
   3 *
   4 * Cleanup unreachable files and optimize the repository.
   5 *
   6 * Copyright (c) 2007 James Bowes
   7 *
   8 * Based on git-gc.sh, which is
   9 *
  10 * Copyright (c) 2006 Shawn O. Pearce
  11 */
  12
  13#include "builtin.h"
  14#include "tempfile.h"
  15#include "lockfile.h"
  16#include "parse-options.h"
  17#include "run-command.h"
  18#include "sigchain.h"
  19#include "argv-array.h"
  20#include "commit.h"
  21
  22#define FAILED_RUN "failed to run %s"
  23
  24static const char * const builtin_gc_usage[] = {
  25        N_("git gc [<options>]"),
  26        NULL
  27};
  28
  29static int pack_refs = 1;
  30static int prune_reflogs = 1;
  31static int aggressive_depth = 250;
  32static int aggressive_window = 250;
  33static int gc_auto_threshold = 6700;
  34static int gc_auto_pack_limit = 50;
  35static int detach_auto = 1;
  36static const char *prune_expire = "2.weeks.ago";
  37static const char *prune_worktrees_expire = "3.months.ago";
  38
  39static struct argv_array pack_refs_cmd = ARGV_ARRAY_INIT;
  40static struct argv_array reflog = ARGV_ARRAY_INIT;
  41static struct argv_array repack = ARGV_ARRAY_INIT;
  42static struct argv_array prune = ARGV_ARRAY_INIT;
  43static struct argv_array prune_worktrees = ARGV_ARRAY_INIT;
  44static struct argv_array rerere = ARGV_ARRAY_INIT;
  45
  46static struct tempfile pidfile;
  47static struct lock_file log_lock;
  48
  49static void git_config_date_string(const char *key, const char **output)
  50{
  51        if (git_config_get_string_const(key, output))
  52                return;
  53        if (strcmp(*output, "now")) {
  54                unsigned long now = approxidate("now");
  55                if (approxidate(*output) >= now)
  56                        git_die_config(key, _("Invalid %s: '%s'"), key, *output);
  57        }
  58}
  59
  60static void process_log_file(void)
  61{
  62        struct stat st;
  63        if (!fstat(get_lock_file_fd(&log_lock), &st) && st.st_size)
  64                commit_lock_file(&log_lock);
  65        else
  66                rollback_lock_file(&log_lock);
  67}
  68
  69static void process_log_file_at_exit(void)
  70{
  71        fflush(stderr);
  72        process_log_file();
  73}
  74
  75static void process_log_file_on_signal(int signo)
  76{
  77        process_log_file();
  78        sigchain_pop(signo);
  79        raise(signo);
  80}
  81
  82static void gc_config(void)
  83{
  84        const char *value;
  85
  86        if (!git_config_get_value("gc.packrefs", &value)) {
  87                if (value && !strcmp(value, "notbare"))
  88                        pack_refs = -1;
  89                else
  90                        pack_refs = git_config_bool("gc.packrefs", value);
  91        }
  92
  93        git_config_get_int("gc.aggressivewindow", &aggressive_window);
  94        git_config_get_int("gc.aggressivedepth", &aggressive_depth);
  95        git_config_get_int("gc.auto", &gc_auto_threshold);
  96        git_config_get_int("gc.autopacklimit", &gc_auto_pack_limit);
  97        git_config_get_bool("gc.autodetach", &detach_auto);
  98        git_config_date_string("gc.pruneexpire", &prune_expire);
  99        git_config_date_string("gc.worktreepruneexpire", &prune_worktrees_expire);
 100        git_config(git_default_config, NULL);
 101}
 102
 103static int too_many_loose_objects(void)
 104{
 105        /*
 106         * Quickly check if a "gc" is needed, by estimating how
 107         * many loose objects there are.  Because SHA-1 is evenly
 108         * distributed, we can check only one and get a reasonable
 109         * estimate.
 110         */
 111        char path[PATH_MAX];
 112        const char *objdir = get_object_directory();
 113        DIR *dir;
 114        struct dirent *ent;
 115        int auto_threshold;
 116        int num_loose = 0;
 117        int needed = 0;
 118
 119        if (gc_auto_threshold <= 0)
 120                return 0;
 121
 122        if (sizeof(path) <= snprintf(path, sizeof(path), "%s/17", objdir)) {
 123                warning(_("insanely long object directory %.*s"), 50, objdir);
 124                return 0;
 125        }
 126        dir = opendir(path);
 127        if (!dir)
 128                return 0;
 129
 130        auto_threshold = (gc_auto_threshold + 255) / 256;
 131        while ((ent = readdir(dir)) != NULL) {
 132                if (strspn(ent->d_name, "0123456789abcdef") != 38 ||
 133                    ent->d_name[38] != '\0')
 134                        continue;
 135                if (++num_loose > auto_threshold) {
 136                        needed = 1;
 137                        break;
 138                }
 139        }
 140        closedir(dir);
 141        return needed;
 142}
 143
 144static int too_many_packs(void)
 145{
 146        struct packed_git *p;
 147        int cnt;
 148
 149        if (gc_auto_pack_limit <= 0)
 150                return 0;
 151
 152        prepare_packed_git();
 153        for (cnt = 0, p = packed_git; p; p = p->next) {
 154                if (!p->pack_local)
 155                        continue;
 156                if (p->pack_keep)
 157                        continue;
 158                /*
 159                 * Perhaps check the size of the pack and count only
 160                 * very small ones here?
 161                 */
 162                cnt++;
 163        }
 164        return gc_auto_pack_limit <= cnt;
 165}
 166
 167static void add_repack_all_option(void)
 168{
 169        if (prune_expire && !strcmp(prune_expire, "now"))
 170                argv_array_push(&repack, "-a");
 171        else {
 172                argv_array_push(&repack, "-A");
 173                if (prune_expire)
 174                        argv_array_pushf(&repack, "--unpack-unreachable=%s", prune_expire);
 175        }
 176}
 177
 178static int need_to_gc(void)
 179{
 180        /*
 181         * Setting gc.auto to 0 or negative can disable the
 182         * automatic gc.
 183         */
 184        if (gc_auto_threshold <= 0)
 185                return 0;
 186
 187        /*
 188         * If there are too many loose objects, but not too many
 189         * packs, we run "repack -d -l".  If there are too many packs,
 190         * we run "repack -A -d -l".  Otherwise we tell the caller
 191         * there is no need.
 192         */
 193        if (too_many_packs())
 194                add_repack_all_option();
 195        else if (!too_many_loose_objects())
 196                return 0;
 197
 198        if (run_hook_le(NULL, "pre-auto-gc", NULL))
 199                return 0;
 200        return 1;
 201}
 202
 203/* return NULL on success, else hostname running the gc */
 204static const char *lock_repo_for_gc(int force, pid_t* ret_pid)
 205{
 206        static struct lock_file lock;
 207        char my_host[128];
 208        struct strbuf sb = STRBUF_INIT;
 209        struct stat st;
 210        uintmax_t pid;
 211        FILE *fp;
 212        int fd;
 213        char *pidfile_path;
 214
 215        if (is_tempfile_active(&pidfile))
 216                /* already locked */
 217                return NULL;
 218
 219        if (gethostname(my_host, sizeof(my_host)))
 220                strcpy(my_host, "unknown");
 221
 222        pidfile_path = git_pathdup("gc.pid");
 223        fd = hold_lock_file_for_update(&lock, pidfile_path,
 224                                       LOCK_DIE_ON_ERROR);
 225        if (!force) {
 226                static char locking_host[128];
 227                int should_exit;
 228                fp = fopen(pidfile_path, "r");
 229                memset(locking_host, 0, sizeof(locking_host));
 230                should_exit =
 231                        fp != NULL &&
 232                        !fstat(fileno(fp), &st) &&
 233                        /*
 234                         * 12 hour limit is very generous as gc should
 235                         * never take that long. On the other hand we
 236                         * don't really need a strict limit here,
 237                         * running gc --auto one day late is not a big
 238                         * problem. --force can be used in manual gc
 239                         * after the user verifies that no gc is
 240                         * running.
 241                         */
 242                        time(NULL) - st.st_mtime <= 12 * 3600 &&
 243                        fscanf(fp, "%"PRIuMAX" %127c", &pid, locking_host) == 2 &&
 244                        /* be gentle to concurrent "gc" on remote hosts */
 245                        (strcmp(locking_host, my_host) || !kill(pid, 0) || errno == EPERM);
 246                if (fp != NULL)
 247                        fclose(fp);
 248                if (should_exit) {
 249                        if (fd >= 0)
 250                                rollback_lock_file(&lock);
 251                        *ret_pid = pid;
 252                        free(pidfile_path);
 253                        return locking_host;
 254                }
 255        }
 256
 257        strbuf_addf(&sb, "%"PRIuMAX" %s",
 258                    (uintmax_t) getpid(), my_host);
 259        write_in_full(fd, sb.buf, sb.len);
 260        strbuf_release(&sb);
 261        commit_lock_file(&lock);
 262        register_tempfile(&pidfile, pidfile_path);
 263        free(pidfile_path);
 264        return NULL;
 265}
 266
 267static int report_last_gc_error(void)
 268{
 269        struct strbuf sb = STRBUF_INIT;
 270        int ret;
 271
 272        ret = strbuf_read_file(&sb, git_path("gc.log"), 0);
 273        if (ret > 0)
 274                return error(_("The last gc run reported the following. "
 275                               "Please correct the root cause\n"
 276                               "and remove %s.\n"
 277                               "Automatic cleanup will not be performed "
 278                               "until the file is removed.\n\n"
 279                               "%s"),
 280                             git_path("gc.log"), sb.buf);
 281        strbuf_release(&sb);
 282        return 0;
 283}
 284
 285static int gc_before_repack(void)
 286{
 287        if (pack_refs && run_command_v_opt(pack_refs_cmd.argv, RUN_GIT_CMD))
 288                return error(FAILED_RUN, pack_refs_cmd.argv[0]);
 289
 290        if (prune_reflogs && run_command_v_opt(reflog.argv, RUN_GIT_CMD))
 291                return error(FAILED_RUN, reflog.argv[0]);
 292
 293        pack_refs = 0;
 294        prune_reflogs = 0;
 295        return 0;
 296}
 297
 298int cmd_gc(int argc, const char **argv, const char *prefix)
 299{
 300        int aggressive = 0;
 301        int auto_gc = 0;
 302        int quiet = 0;
 303        int force = 0;
 304        const char *name;
 305        pid_t pid;
 306        int daemonized = 0;
 307
 308        struct option builtin_gc_options[] = {
 309                OPT__QUIET(&quiet, N_("suppress progress reporting")),
 310                { OPTION_STRING, 0, "prune", &prune_expire, N_("date"),
 311                        N_("prune unreferenced objects"),
 312                        PARSE_OPT_OPTARG, NULL, (intptr_t)prune_expire },
 313                OPT_BOOL(0, "aggressive", &aggressive, N_("be more thorough (increased runtime)")),
 314                OPT_BOOL(0, "auto", &auto_gc, N_("enable auto-gc mode")),
 315                OPT_BOOL(0, "force", &force, N_("force running gc even if there may be another gc running")),
 316                OPT_END()
 317        };
 318
 319        if (argc == 2 && !strcmp(argv[1], "-h"))
 320                usage_with_options(builtin_gc_usage, builtin_gc_options);
 321
 322        argv_array_pushl(&pack_refs_cmd, "pack-refs", "--all", "--prune", NULL);
 323        argv_array_pushl(&reflog, "reflog", "expire", "--all", NULL);
 324        argv_array_pushl(&repack, "repack", "-d", "-l", NULL);
 325        argv_array_pushl(&prune, "prune", "--expire", NULL);
 326        argv_array_pushl(&prune_worktrees, "worktree", "prune", "--expire", NULL);
 327        argv_array_pushl(&rerere, "rerere", "gc", NULL);
 328
 329        gc_config();
 330
 331        if (pack_refs < 0)
 332                pack_refs = !is_bare_repository();
 333
 334        argc = parse_options(argc, argv, prefix, builtin_gc_options,
 335                             builtin_gc_usage, 0);
 336        if (argc > 0)
 337                usage_with_options(builtin_gc_usage, builtin_gc_options);
 338
 339        if (aggressive) {
 340                argv_array_push(&repack, "-f");
 341                if (aggressive_depth > 0)
 342                        argv_array_pushf(&repack, "--depth=%d", aggressive_depth);
 343                if (aggressive_window > 0)
 344                        argv_array_pushf(&repack, "--window=%d", aggressive_window);
 345        }
 346        if (quiet)
 347                argv_array_push(&repack, "-q");
 348
 349        if (auto_gc) {
 350                /*
 351                 * Auto-gc should be least intrusive as possible.
 352                 */
 353                if (!need_to_gc())
 354                        return 0;
 355                if (!quiet) {
 356                        if (detach_auto)
 357                                fprintf(stderr, _("Auto packing the repository in background for optimum performance.\n"));
 358                        else
 359                                fprintf(stderr, _("Auto packing the repository for optimum performance.\n"));
 360                        fprintf(stderr, _("See \"git help gc\" for manual housekeeping.\n"));
 361                }
 362                if (detach_auto) {
 363                        if (report_last_gc_error())
 364                                return -1;
 365
 366                        if (gc_before_repack())
 367                                return -1;
 368                        /*
 369                         * failure to daemonize is ok, we'll continue
 370                         * in foreground
 371                         */
 372                        daemonized = !daemonize();
 373                }
 374        } else
 375                add_repack_all_option();
 376
 377        name = lock_repo_for_gc(force, &pid);
 378        if (name) {
 379                if (auto_gc)
 380                        return 0; /* be quiet on --auto */
 381                die(_("gc is already running on machine '%s' pid %"PRIuMAX" (use --force if not)"),
 382                    name, (uintmax_t)pid);
 383        }
 384
 385        if (daemonized) {
 386                hold_lock_file_for_update(&log_lock,
 387                                          git_path("gc.log"),
 388                                          LOCK_DIE_ON_ERROR);
 389                dup2(get_lock_file_fd(&log_lock), 2);
 390                sigchain_push_common(process_log_file_on_signal);
 391                atexit(process_log_file_at_exit);
 392        }
 393
 394        if (gc_before_repack())
 395                return -1;
 396
 397        if (run_command_v_opt(repack.argv, RUN_GIT_CMD))
 398                return error(FAILED_RUN, repack.argv[0]);
 399
 400        if (prune_expire) {
 401                argv_array_push(&prune, prune_expire);
 402                if (quiet)
 403                        argv_array_push(&prune, "--no-progress");
 404                if (run_command_v_opt(prune.argv, RUN_GIT_CMD))
 405                        return error(FAILED_RUN, prune.argv[0]);
 406        }
 407
 408        if (prune_worktrees_expire) {
 409                argv_array_push(&prune_worktrees, prune_worktrees_expire);
 410                if (run_command_v_opt(prune_worktrees.argv, RUN_GIT_CMD))
 411                        return error(FAILED_RUN, prune_worktrees.argv[0]);
 412        }
 413
 414        if (run_command_v_opt(rerere.argv, RUN_GIT_CMD))
 415                return error(FAILED_RUN, rerere.argv[0]);
 416
 417        if (auto_gc && too_many_loose_objects())
 418                warning(_("There are too many unreachable loose objects; "
 419                        "run 'git prune' to remove them."));
 420
 421        return 0;
 422}